Organic lenses

*Caution contains specific terms. Organic lenses are used in the manufacture of prescription glasses. They are a type of plastic that has characteristics suitable for corrective lenses. According to a study conducted in 2018, over 380 million tons of plastic were produced. And nearly 40% of its production is intended for the manufacture of packaging.

What is plastic?

These are macromolecular compounds with different ways of connecting individual molecules and different ways of crosslinking. Or in other words, one product that has multiple applications.

Classification of plastics

Thermoplastics

They are linearly connected macromolecular chains, uncrosslinked, with the ability to be repeatedly heat treated. They change their shape and viscosity at a certain temperature. Most plastic objects that surround us are thermoplastics. For example, clothing, joinery, furniture and almost all packaging.

Thermosets

These are spatially linked, through polymerization, macromolecular chains with the possibility of a single thermal treatment. They are the opposite of thermoplastics and take their shape when heated. For this reason, they are used to make elements that have a risk of ignition, such as plugs, sockets, electrical switches and others. About 90% of the recycled plastic in the world belongs to the group of thermoplastics. In general, this is a product that does not have a good reputation, but in terms of the optical world, its application improves the comfort of wearing glasses. Unlike mineral lenses, organic ones are lighter and less fragile, which makes them preferred in mass use.

Characteristic properties of plastics

• diverse refractive index
• low optical uniformity
• low hardness
• small table
• easily soluble in solvents
• high plasticity and elasticity
• over time they change their properties

All these indicators pave their way into the Spectacle World we live in. Organic lenses are easy to manufacture, with good performance in terms of vision, strong and light are some of their most important characteristics.

Types of plastics for optical building materials

Polymethyl methacrylate

It has similar properties to optical glass. When heated or loaded, double refraction occurs. It has a very high thermal expansion coefficient. It has low hardness, which makes it scratch resistant. Additional layers characteristic of dioptric lenses are easily applied to this material.

Polyvinyl alcohol

It is a thermoset, light-resistant, soluble in organic solvents. It is used for polarizing film, light filters for photography, as well as for making polarizing lenses.

Polydiethmenglycoldoallyl carbonate

It is a scratch-resistant duroplast, absorbs ultraviolet rays, and is used for aspheric lenses, mono and bifocal glasses, as well as for prisms in optical devices.

Hydroxyethyl methacrylate

This is a water-resistant plastic. It is produced in several types depending on its water content. It is used to make soft contact lenses. Plastic is all around us. Fortunately, many eyewear manufacturers have started using natural products that are not harmful to the environment, but at the same time have the same characteristics. An example of this are glasses Etnia Barcelona and  ROLF SpectaclesFinally, here are a few curious things about plastic as a product of modern times.

Interesting facts about plastic

1. The mass introduction of plastic as a product began in the second half of the 20th century.
2. Between 1950 and 2017, about 9.2 billion pieces of plastic were produced. Only 10% of it was recycled.
3. In 1978, Coca-Cola was the first to decide to replace its glass bottle with a plastic one.
4. Plastic generates many health risks because numerous chemicals are added to its composition to give it the desired characteristics.
5. Our clothes are made of plastic.